Update the error message when checking for pcap_loop()

Add a first error case when trying to build a 32-bit tcpdump with a
64-bit libpcap or vice versa.

(cherry picked from commit 42116158c3731c52c30cb27767b287c5fa4d4471)

[skip ci]

diff --git a/aclocal.m4 b/aclocal.m4
index 8a7a08cdaff8bb7b8f86c152eaac74ba37d96af3..65a4a9e685b7d33207b4d6e901232f196479590e 100644 (file)
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -856,8 +856,10 @@ AC_DEFUN(AC_LBL_LIBPCAP,
     AC_CHECK_FUNC(pcap_loop,,
     [
         AC_MSG_ERROR(
-[This is a bug, please follow the guidelines in CONTRIBUTING.md and include the
-config.log file in your report.  If you have downloaded libpcap from
+[
+1. Do you try to build a 32-bit tcpdump with a 64-bit libpcap or vice versa?
+2. This is a bug, please follow the guidelines in CONTRIBUTING.md and include
+the config.log file in your report.  If you have downloaded libpcap from
 tcpdump.org, and built it yourself, please also include the config.log
 file from the libpcap source directory, the Makefile from the libpcap
 source directory, and the output of the make process for libpcap, as